Patterns

Question 1

List pattern examples in JDK

Answer 1

Builder, Factory method,
Prototype - Objects.clone()
Singleton - System
Adapter - Arrays.asList()

Chain of responsibility - logger
Iterator - Iterator
Ptroxy - reflection

Observer - listener

Question 2

Facade

Answer 2

Structural
Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use

Question 3

Proxy

Answer 3

Structural
Provide placeholder for another object to control access to it.

Question 4

Decorator

Answer 4

Structural
attach additional responsibilities to an object dynamically
alternative to subclassing for extending functionality

Question 5

Strategy

Answer 5

Define a family of algorithms, encapsulate each one, and make them interchangeable.
Strategy lets the algorithm vary independently from clients that use it.

Question 6

Observer

Answer 6

Define a one-to-many dependency between objects so that when one object changes state,
all its dependents are notified and updated automatically.

Question 7

Bridge

Answer 7

Decouple an abstraction from its implementation so that the two can vary independently.

Question 8

Singleton

Answer 8

Ensure a class only has one instance, and provide a global point of access to it.

Question 9

Flyweight

Answer 9

minimizes memory use by sharing as much data as possible with other similar objects

Question 10

Builder

Answer 10

Separate the construction of a complex object from its representation
so that the same construction process can create different representations.